Electric switch



June 25, 1935.

F. MENZEL ELECTRIC SWITCH Filed 001 5. 1931 Fig. 4.

Patented June 25, 1935 I UNITED STATES ELECTRIC swr'ron Friedrich Menzel, Stuttgart, Germany, assignor to Robert Bosch Aktiengesellschaft, Stuttgart,

Germany L Application October 5, 1931, Serial No. 567,079 In Germany October 9, 1930 4 Claims.

The present invention relates to electric switches of the combined electro-magnetic regulator and cut-out switch type suitable for electrical systems on motor vehicles, such as is disclosed in my Patent No. 1,820,361, dated August 25, 1931, forexample.

In switches of this type the current coil must be kept small, corresponding to the requirements of the regulator. The automatic cut-out switch under normal conditions of working, with the switch closed, afford a definite contact pressure, so that the switch shall not open prematurely owing to vibrations of the vehicle, and it must curve or bend in the desired manner on becoming heated by the sparking of the circuit-breaker.

These two properties are not always easily combined in a single spring.

The object of the present invention is to remove this difficulty by securing the bimetallic spring secured to a spring of the usual material. The advantage is thereby attained that the usual spring can be selected to correspond to the desired contact pressure and the bimetallic spring corresponding to the desired sensitiveness to heat.

In the drawing an example of construction of the invention is illustrated in which:

Figure l is a sectional view of the regulator switch, and

Figure 2 shows the contact spring of the switch on an enlarged scale.

The regulator switch is shown in Figure 1 with the switch in the openposition, and apart from the construction of the contact spring is of the usual construction. The switch contact spring consists of two parts. namely, a spring a of the usual material and a bimetallic spring b riveted thereto wheh carries the contact 9 of the switch. The numeral l2 designatesjhe fixed counter contact of the switch.

The bimetallic spring 1) curves, under the infiuence of the sparking of the cut-out, towards the fixed contact l2 on a short-circuit taking place, so that the switch is thereby closed. On cooling, the bimetallic spring 1) curves back again into the position shown in the drawing in which the switch is opened.

In this construction the contact pressure on the switch can be selected for the temperatures occurring in normal working. Further, the sparks 5 arising by the opening and closing of the switch on a short circuit are smaller than in a bimetallic spring which bends upwards on heating from the counter-contact, because the contact spring on becoming heated hasthe tendency to close the switch.

The composition of the switch contact spring of two parts a and b enables the spring force and the curvature on heating to be obtained by this means in the desired manner. 5

Instead of riveting the bimetallic spring I) to the spring a, the two may also be connected together by welding or in any suitable other manner.

The object 01' the invention is not limited to the constructional form of the regulator switch illustrated. For example, the spring 0. instead of being fastened to the frame of the magnet may also be fastened to the armature.

I declare that what I claimis: I

.1. A combined electromagnetic cut-out and regulator for the electrical systems of motor vehicles comprising a core of magnetic material, a voltage coil and a current coil connected to the dynamo and coiled about said core, an armature, means for regulating the output of said dynamo upon movement of said armature, a pair of cutout contacts connected in series with said current coil and the battery, a bimetal spring carrying one of said contacts and a spring of a single ma- 3 terlal upon which said bimetal spring is mounted.

2. A combined electromagnetic cut-out and regulator for the electrical systems of motor vehiclescomprising, means for regulating the dynamo oi the system, a pair of cut-out contacts, means for operating said contacts and means for preventing the operation of said contacts upon short circuiting including a bimetal spring carrying one of said contacts adapted to be heated by the sparks caused by the opening of said contacts to cause the spring to distort to prevent the operation of said contacts and a single metal spring mounting for said bimetal spring whereby the desired pressure between the contacts may be maintained for normal working while permitting the choice of ideal dimensions for the bimetal spring.

3. A contact member for an electromagnetic cut-out and regulator switch for the electrical systems of motor vehicles comprising a bimetai spring carrying one of the cut-out contacts and a single spring supporting said bimetal spring, said bimetal spring being operated by the heat generated by sparks caused by the opening or said contacts.

4. A contact member for an electromagnetic cut-out and regulator switch for the electrical systems of motor vehicles comprising a bimetal spring carrying one o! the cut-out contacts and a single spring supporting said bimetal spring, said single spring being secured against movement at one end but being otherwise freely 5 movable.

FRIEDRICH MENZEL. 

